* {
  margin: 0;
  padding: 0;
}
body {
  height: 100vh;
  display: flex;
  justify-content: center;
  align-items: center;
}
/* 使用更具体的选择器避免全局样式冲突 */
body .container {
  border: 1px solid #38ada9;
  display: block;
  min-height: auto;
  flex-direction: unset;
  align-items: unset;
  justify-content: unset;
  background: none;
  font-family: unset;
  color: unset;
}
/* 标签栏 */
.nav {
  display: flex;
}
.nav .item {
  width: 140px;
  height: 108px;
  border-right: 1px solid #38ada9;
  border-bottom: 1px solid #38ada9;
  display: flex;
  justify-content: center;
  align-items: center;
  cursor: pointer;
  /* 相对定位 */
  position: relative;
  /* 溢出隐藏 */
  overflow: hidden;
}
.nav .item:last-child {
  border-right: none;
}
/* 图标背景圆 */
.nav .item::before {
  content: '';
  width: 80px;
  height: 80px;
  background-color: #38ada9;
  border-radius: 50%;
  /* 绝对定位 */
  position: absolute;
  /* 过渡效果 */
  transition: 0.3s;
}
.nav .fa {
  color: #fff;
  position: relative;
  font-size: 36px;
}
/* 标签选中态样式 */
.nav .item.active::before {
  width: 150%;
  height: 150%;
}
/* 内容区 */
.content {
  width: 100%;
  height: 300px;
  position: relative;
}
section {
  width: 100%;
  height: 100%;
  display: flex;
  justify-content: center;
  align-items: center;
  position: absolute;
  /* 默认隐藏 */
  opacity: 0;
  /* 不透明度改变时的过渡效果 */
  transition: opacity 0.4s;
}
section span {
  font-size: 80px;
  font-weight: bold;
  color: #38ada940;
}
/* 内容区选中态样式 */
section.active {
  opacity: 1;
}
